目的:观察邻苯二甲酸二乙基己酯(DEHP)及代谢产物邻苯二酸-单-2-乙基己酯(MEHP)对幼鼠睾丸组织转化生长因子-β1(TGF-β1)表达和端粒酶活性的影响,探讨DEHP和MEHP损害生精功能可能的机制。方法:生后2周龄的Wistar雄性幼鼠96只,随机分8组,每组12只。随机选择1组行生理盐水[0.9%NS0.2 ml/(kg.d),喂养3周]灌胃,作为正常对照组(NC组);再选1组行环磷酰胺[CTX 100 mg/(kg.d),喂养1周]灌胃,作为阳性对照组(PC组);余各组分别用DEHP、MEHP按低剂量[100 mg/(kg.d),喂养3周]、中剂量[200 mg/(kg.d),喂养2周]、高剂量[300 mg/(kg.d),喂养1周]灌胃制作动物模型。观察不同时期、不同剂量下睾丸组织精子形态变化,光镜下计数精子头部及畸形率;应用免疫组化SABC法及RT-PCR法检查睾丸组织TGF-β1的表达,并测定面密度;ELISA法检查睾丸组织中端粒酶活性。结果:①睾丸组织内精子形态变化:用药组精子数量减少,出现精子断头、无钩、双尾等畸形精子;在光镜下精子计数,与NC组比较,用药各组精子头部显著减少(P<0.05),畸形率增加(P<0.05),但高剂量短时间用药组与低剂量长时间用药组比较,差异无统计学意义(P>0.05)。②睾丸组织TGF-β1的表达变化:NC组低表达,DEHP及代谢产物MEHP染毒各组生精细胞内表达增多,PC组大量表达,阳性细胞呈黄褐色,主要分布于胞膜及胞质。NC组面密度为0.156 0±0.003 5、TGF-β1mRNA为1.51±0.20,PC组面密度为0.534 0±0.003 1、TGF-β1 mRNA为8.43±1.75;用药的DEHP组面密度均值为0.289 0±0.003 6、TGF-β1 mRNA为3.83±1.57,MEHP组面密度均值为0.284 0±0.003 1、TGF-β1 mRNA为3.51±1.41,用药各组与NC组、PC组比较差异有统计学意义(P<0.01),但高剂量短时间用药组与低剂量长时间用药组比较,差异无统计学意义(P>0.05);③睾丸组织中端粒酶活性:与NC组比较,用药各组睾丸组织中端粒酶活性下降(P<0.05),高剂量短时间用药组与低剂量长时间用药组比较,差异无统计学意义(P>0.05)。结论:DEHP及代谢产物MEHP对幼鼠生精功能有明显损害,其损害机制可能与DEHP及代谢产物MEHP诱导睾丸组织TGF-β1的表达水平升高、端粒酶活性降低有关。 AIM: To observe the expression of transforming growth factor-β1 (TGF-β1) in the testis tissue of young rats induced by diethylhexyl phthalate (DEHP) and its metabolite phthalate-mono-2-ethylhexyl ester (MEHP) And telomerase activity, and to explore the possible mechanisms by which DEHP and MEHP impair the function of spermatogenesis. Methods: A total of 96 Wistar male pups aged 2 weeks were divided into 8 groups randomly, 12 in each group. A group of normal saline (0.9% NS0.2 ml / (kg · d) for 3 weeks) was given as a normal control group (NC group) randomly. One group was given cyclophosphamide [CTX 100 mg / (kg.d) and fed for 1 week] were given as the positive control group (PC group). The rest groups were treated with DEHP and MEHP respectively at low dose [100 mg / (kg · d) for 3 weeks] [200 mg / (kg · d) for 2 weeks] and high dose [300 mg / (kg · d) for 1 week]. The morphological changes of spermatozoa were observed at different time and different doses, the sperm head and deformity were counted under light microscope. The expression of TGF-β1 in testes was detected by immunohistochemistry and RT-PCR, Act test of telomerase activity in testicular tissue. Results: ①Sperm morphology changes in testis: the number of sperm in treatment group decreased, there were sperms broken, no hook, two-tailed and other abnormal sperm; sperm count under light microscope, compared with NC group, the sperm head of each group was significantly reduced (P <0.05), and the rate of deformity increased (P <0.05). However, there was no significant difference between the high-dose short-term medication group and the low-dosage long-term medication group (P> 0.05). ② The expression of TGF-β1 in testis tissue: The expression of TGF-β1 in NC group was lower than that in NC group, the expression of DEHP and MEHP increased significantly in spermatogenic cells, and the expression of TGF-β1 in PC group was heavy brown, mainly distributed in membrane and cytoplasm . The surface density of NC group was 0.156 0 ± 0.003 5, the expression of TGF-β1 mRNA was 1.51 ± 0.20, the surface density of PC group was 0.534 0 ± 0.003 1 and the level of TGF-β1 mRNA was 8.43 ± 1.75. The average density of DEHP group was 0.289 0 ± 0.003 6, TGF-β1 mRNA was 3.83 ± 1.57, mean surface density of MEHP was 0.284 ± 0.003 1, and TGF-β1 mRNA was 3.51 ± 1.41, there was significant difference between PC group and NC group <0.01). However, there was no significant difference between the high-dose short-term drug group and the low-dose long-term drug group (P> 0.05). ③ The telomerase activity in testis: Compared with NC group, (P <0.05). There was no significant difference in the telomerase activity between the high-dose short-term drug group and the low-dose long-term drug group (P> 0.05). CONCLUSION: DEHP and its metabolite MEHP significantly impair the function of spermatogenesis in immature rats. The possible mechanism is that DEHP and MEHP can induce the increase of TGF-β1 expression and the decrease of telomerase activity in testis.